TMZ reports that Swift wrote the EDM star's recent hit
featuring Rihanna, "This is What You Came For." The track
was the spiritual sequel to Harris and Rih Rih's monster
collaboration "We Found
Love," and placed high on the Billboard charts when
it was released at the end of April.

Sources close to Swift told TMZ that she wrote tune for Harris,
and recorded a demo on her iPhone of herself singing it while
playing piano and sent it. He's said to have loved it, but the
two supposedly decided not to make Swift's role in the creation
public, fearing that their status as a celebrity couple might
overshadow the song.

So far so good, but TMZ's source is claiming that the problem
came when Harris was too overzealous in minimizing Swift's role.
When the song came out, the producer did a radio interview
with Ryan Seacrest.

"Will you do a collaboration with your girlfriend?" the host
asked?

"You know we haven't even spoken about it," he said. "I can't see
it happening though."

For some reason, this exchange was the breaking point, and Swift
felt disrespected. Update: A rep for
Swift confirmed to
People that, yes, the singer wrote "This Is What You
Came For."

This could mean she retains the rights that could prevent Harris
from performing the track. The irony here is that Harris once did
that exact same thing to one of his exes, Rita Ora,
after they broke up.